Russia keeps Australian Greenpeace activist Colin Russell locked up until at least February 24

GREENPEACE says a Russian court's decision to extend an Australian activist's detention has turned the case into "a circus".

Tasmanian Colin Russell was among 30 Greenpeace activists arrested by Russian authorities two months ago following an at-sea protest against Arctic oil drilling.

Yesterday, a Saint Petersburg court extended Mr Russell's pre-trial detention until February 24, while a request for bail or house arrest was denied.

Earlier, the court unexpectedly released two activists, a Russian photographer and a doctor, on bail.

Mr Russell was the first of the 30 detained activists to have his case heard and the ruling by the court creates a precedent that could mean all those arrested will have their detention extended in a similar fashion.

The measure means that all the 30 activists may remain in detention until the Winter Olympic Games in Sochi are over in Russia on February 23.

The judge at Saint Petersburg's Primorsky court ordered to "leave the pre-trial restrictions unchanged until February 24," and a request for bail or house arrest was denied.

"I love you all. I love everybody," Mr Russell, 59, said after the judge announced her decision.

"I am not a criminal," he said in comments released by Greenpeace.

Greenpeace International executive director Kumi Naidoo said: "This case is now a circus."

"We will continue to pursue every legal avenue we can, and leave no stone unturned, until each and every one of them is home with their families," he said in a statement.

Earlier in the day Mr Russell insisted he was innocent.

"I have spent two months in detention, having done nothing wrong," Mr Russell, looking visibly upset, said from a metal cage in the courtroom.

"I have not committed a crime so I have nothing to run from."

Four more Greenpeace activists and two freelance journalists face hearings in Saint Petersburg on Monday.

The activists have been put in pre-trial jail after their ship was seized at gunpoint by Russian security forces in September following their open-sea protest against Arctic oil drilling.

The activists were first charged with piracy which carries a maximum punishment of 15 years but the charges were later changed to hooliganism which carries a sentence of up to seven years.

The activists were first held in and around the city of Murmansk above the Arctic Circle but were earlier this month transferred to Saint Petersburg.